qail-core

The AST-native query builder — No application SQL string building, no ORM magic, just type-safe expressions.

Why AST-Native?

Approach	How it works	Safety Level
String-based	SQL as strings	Requires parameterization
ORM	Macros generate SQL	Compile-time safe
AST-Native (QAIL)	Typed AST → Protocol bytes	Structurally safe

QAIL builds queries as an Abstract Syntax Tree that compiles directly to protocol bytes.

SQL string = text query assembled in application code.
SQL bytes = protocol frames + typed values emitted from AST.
Scope = QAIL removes app-side SQL interpolation on the AST path.

Installation

[!CAUTION] Release Candidate: QAIL is now in the release-candidate phase. The API is near-stable and battle-tested in production. Breaking changes are expected to be rare and limited to critical correctness/security fixes before 1.0.

[dependencies]
qail-core = "0.26.3"

Quick Start

use qail_core::{Qail, Operator};
use qail_core::ast::builders::*;

// Build a query as typed AST
let cmd = Qail::get("users")
    .columns([col("id"), col("name"), col("email")])
    .filter(eq("active", true))
    .order_by([("created_at", Desc)])
    .limit(10);

// Use with qail-pg driver
let rows = driver.fetch_all(&cmd).await?;

Ergonomic Expression Builders

use qail_core::ast::builders::*;

// Aggregates with FILTER
count_filter(vec![eq("status", "active")]).alias("active_users")

// Time expressions  
now_minus("24 hours")  // NOW() - INTERVAL '24 hours'

// CASE WHEN
case_when(gt("score", 80), text("pass"))
    .otherwise(text("fail"))
    .alias("result")

// Type casting
cast(col("amount"), "float8")

Features

Type-safe expressions — Compile-time checked query building
Ergonomic builders — count(), sum(), case_when(), now_minus()
Full SQL support — CTEs, JOINs, DISTINCT ON, aggregates with FILTER
JSON operators — ->, ->>, @>, ?
Schema parser — Parse DDL into structured AST

Ecosystem

Crate	Purpose
qail-core	AST builder, parser, expression helpers
qail-pg	PostgreSQL driver (AST → wire protocol)
qail	CLI tool for migrations and schema ops

License

Apache-2.0

🤝 Contributing & Support

We welcome issue reports on GitHub! Please provide detailed descriptions to help us reproduce and fix the problem. We aim to address critical issues within 1-5 business days.

qail-core 0.26.4